Installing Cruise Control

Two different kits certainly makes it sound like something in the car is missing. I wasn't able to do my fog lights through factory wiring because the internal relays in the fuse box weren't populated on the board. If it were me I would jump on https://techinfo.toyota.com and follow the troubleshooting guide for the factory cruise control. It will cost a few dollars, but its probably the best way to know exactly what you're missing.

 

Any luck?

 

I tried to install cruise control .Fortunately ,all the wiring was already present (HV ECU to brake switch and HV ECU to clock spring). It did not have double throw brake switch but i shorted the wires just to check.the funtionality but unfortunately it doesnt work. I can see CRUISE lamp in dashboard but it never comes ON. I dont know what is the issue.

 

Surprisingly mine worked. Don't know how but the guy who helped me just changed the polarity of brake switch wires. I did not understand this logic but anyhow the result is awesome. I used the aftermarket cruise control lever.

 

That's a good news

 

I'm having the same issue with my 2018 Prius C. I ordered an aftermarket kit with the cruise control stick and two wires for ground and ecm control. I'm pretty sure that the wires are in snug. When I turn on the car and press the cruise on/off button, nothing happens. Local shop wants over $600 dollars to install themselves, heck no. Any ideas?

I'm going to try refitting wires and stock but I'd love some feedback.

Edit: just read the rostra manual linked above by Bonanzo, I put the brown wire in the wrong pin. Will update this post after I rewire.

 

I wish I would have found this post earlier. I used the same Rostra kit you did, but I’m not sure what the other one you used was.

I had a major issue with my install, where the wires the instructions say to use are not the correct ones. You have a wire going from the steering wheel down to the box down by your left foot. The pin connector at the steering wheel was not the same as the pin connector by your feet. So you plug it into the steering wheel, run it down, and it goes into the box by your feet but it does NOT click in. The solution is to just take 2 wires that come with the kit that work for both ends, and just splice them together. Not a huge deal but would have liked to know that myself.

Is this the same issue you were having?

Side note, the Rostra Technical Support was extremely unhelpful, so anyone else having issues might be better off not relying on them.

 

The process for depinning those is a nightmare. As someone who spent probably 2 days troubleshooting that problem, and bought a whole depinning kit on amazon only for it not to work, please share your results.

Currently there is nobody on the internet who has explained how to depin those in detail. If you could post pictures walking through the process, tools required, etc. you’d be doing a great service.

best of luck to you!

 

No, I'm not sure I know what you are talking about with respect to the splicing of wires. I rewired but I still had the same result. Have an appointment scheduled for august 5th to get it installed. Found a shop that's going to charge closer to $420. Which is better than what I had found before. If I can't figure it out before then, it's not really worth the hassle to do it myself. Frustrating because it really shouldn't be that hard.

 

So I found an ECU diagram for my model year (2016-2018). Looks like it refers to splicing. But also, my G57 harness already has a wire in pin 6 so does that mean I don't have to splice, just ground?

 

OK! So I got it working! Did a little jig next to my car. What friggin relief.

I had installed everything correctly except for the ECU side of brown cruise control wire. In the attached picture you'll see that the Rostra 2012-15 cruise control instruction manual says that pin 28 is on the bottom most right most side of the G57 harness. Which it most likely is the cruise circuit pin on the 2015 model of the Prius C. But it looks like the 2016-2020 Prius C model's cruise circuit pin is on the top most right hand side of the same G57 harness. I had taken a picture intended for troubleshooting but I noticed the engraved "28" and "35" on the side of the harness and Facepalmed. After 2015, toyota decided to flip the pins on me! :O Really annoying as there isn't any new instructions on how to install cruise control on 2016 prius c's and up. Welll now you know. Hope someone finds this useful!

 

So I took the plunge. I bought a kit from Redline, the Rostra kit. 250-1836 is part number.
Did the steps below, but no light on the dash and no cruise. So I may take it to a local garage and see if they can check the wiring.

Note: I made sure everything clicked into place and triple checked everything was in tight/clicked.

Start off, I figured out how to take off the trim.
Disconnected the battery negative terminal.
Took off the airbag the the steering wheel.

I had to connect the wiring to the cruise control switch (it was in the bag separately, but only went in one way so no big deal), then screwed in the two screws for the control switch, then ran wiring to the connector in the steering wheel at the top (and I cut off the extra ground).

(these are the directions)
MOUNT CRUISE CONTROL SWITCH WITH TWO (2) PHILLIPS SCREWS PROVIDED. REMOVE GROUND TERMINAL FROM ROSTRA CRUISE CONNECTOR AND DISCARD. PLUG IN CRUISE SWITCH CONNECTOR ENSURING TO RE-CONNECT GROUND TERMINAL. FIGURES 10-11

(not sure why it says reconnect ground terminal after it says to discard it and the video shows cutting it off).

Then ran the black ground wire from pin two under the steering wheel to the bolt under the dash.

INSERT THE CLOCK SPRING TERMINAL FROM THE BLACK CRUISE GROUND HARNESS INTO PIN 2 OF CONNECTOR G5 CAREFULLY LOCKING TERMINAL INTO PLACE.

ROUTE THE GROUND HARNESS ALONG THE FACTORY HARNESS TO THE 10MM BOLT AS SHOWN IN FIGURE 15. REMOVE THE 10MM BOLT AND INSTALL THE RING TERMINAL FROM THE BLACK CRUISE GROUND HARNESS.

Then ran the brown wire, again below the steering wheel, from pin one to the ECM harness, pin 22 (for the prius C 2012).

INSERT THE CLOCK-SPRING TERMINAL FROM THE BROWN (59B-05877) CRUISE ECM HARNESS TO PIN 1 (CRUISE CIRCUIT) OF CONNECTOR G5 CAREFULLY LOCKING TERMINAL INTO PLACE.

INSERT ECM TERMINAL FROM THE BROWN (59B-05877) ECM HARNESS INTO PIN 22 (CRUISE CIRCUIT) OF CONNECTOR G58.

I have left the trim off - figured I would make sure it works before I put things back. But no luck.

Any advice or tricks before I take it into the shop?

Campbell

 

Got it to work. It really is all about putting the wires into the ECM controller. I watched the video online and you have to pull out the tab holding the wires in the ECM...I thought I had, but not far enough out.... wired went in deeper and then cruise worked. Also, if you haven't taken the trim off before, most of it snaps off but you have to go slowly and carefully. The trim around the back seat (covering the battery) has these pins that hold it in - you have to push in the round center and then pull out the black pin (I learned that the hard way after having cracked one).

 

Hi! I purchased a cruise control kit from eBay(picture below) which came with the switch, wire harness and lid for my 2014 Prius C One. However, the ground wire is about 6 inches long(not enough), and the wire which should plug into the ECM does not look particularly good quality. The ECM wire is molex on both ends, and ground wire is molex on one end, and ring on other. If I were to just look for buying better quality replacements of these wires, what I should be searching for? anyone know of their specs? Thanks,